It's been a while, but I don't think you'll find CO's business class to be as good as BA Club.
The biggest issue with transferring at EWR is that you'll need to clear immigration/customs there, which can be time-consuming if you land at a popular time of day (though nothing like as bad as JFK can get). I've never flown direct to IAH, but I imagine there's much less international traffic, hence less immigration queues.